Certain primates, including humans, engage in oral sex. The practice has been documented in bonobos as well. But now researchers have documented fellatio in bats, marking the first time oral sex has been seen in an animal other than a primate.
Biologist Libiao Zhang made the discovery while studying the behavior of short-nosed fruit bats, Cynopterus sphinx, in Guangzhou, China. Zhang and his team placed males and females of this species in cages outfitted like mini love suites, mimicking where the bats would have sex in the wild. Little did the bats know that they were being spied upon with infrared cameras that sent images back to Zhang's lab.
Here's what the researchers saw, according to Cassandra Brooks of Science Now Daily News : "The males
built tents out of Chinese fan-palm leaves to attract the females. And
both sexes groomed each other during courtship. But then came the
shocker: After the male mounted the female from behind, she bent over
and began licking his penis."
(Image credit: Gareth Jones)
Brooks added, "Of the 20 observed mating bat pairs, 70% of the females performed fellatio on the males, the team reports online this week in PLoS ONE.
The males never withdrew while being licked, and the authors found that
the longer a female licked, the longer copulation lasted (for each
second of licking, the female bats gained 6 seconds of copulation). The
team speculates that licking helps maintain the male's erection, and
that the saliva increases lubrication, both of which may prolong
intercourse. In all, fellating females mated for an average of 4
minutes, twice as long as the other females."
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It's possible that females prolong sex to facilitate sperm transport, Zhang and his colleagues theorize, or it could help to keep the males focused on their present partner and prevent them from seeking other female company.
One of the most interesting speculations, in my view, is that oral sex could actually help to protect its participants from sexually transmitted disease. Although saliva can carry infectious agents, it also contains antimicrobes. There's something even Hugh Hefner has probably never investigated.